The Neuropsychology Core/Laboratory (NL) will have three related functions: 1) The NL will serve as a resource for current and future investigators using the CRC/GAD by providing a standard Core neuropsychological assessment for all subjects recruited by the CIL and offering consultation service to collaborating investigators on appropriate neuropsychological constructs and assessment procedures. The Director of the NL has experience as a funded investigator of the neuropsychological consequences of brain dysfunction and geriatric depression and will direct a program of studies to improve the precision and validity of existing measures, develop new neuropsychological assessment instruments, and acquire site-specific normative data. 2) The NL will be a resource for consultation and training of junior investigators in methods of assessment of disorders in higher cortical functions and investigation of the neuropsychological aspects of geriatric depression. 3) The NL will function as a research laboratory with three primary foci: a) the determination of depression-specific cognitive deficits, b) the determination of predictors of dementia in a geriatric depressive population, and c) the determination of the effects of antidepressant medication on neuro-cognitive functioning. This research agenda will be pursued by supporting several funded studies on depression as well as three pilot projects each relevant to one of the three research foci.